It’s hard to get into Harvard, even if you’ve done it before.

Mark Zuckerberg, head of Meta, and Bill Ackman, head of the Pershing Square hedge fund, discovered as much, in their failed push to get dissident candidates onto the Harvard Board of Overseers, one of the university’s two governing bodies.

The candidates — a slate of four backed by Mr. Ackman and one candidate backed by Mr. Zuckerberg — said on Friday that they had not collected enough petition signatures to get on the April ballot for election to the board.

“We are disappointed but greatly appreciate all the support,” Zoe Bedell, an assistant U.S. attorney, who ran on the Ackman slate, said in a statement on Friday. “We look forward to trying again next year.”

Their failure raised the question of how much support existed for Mr. Ackman’s persistent campaign against Harvard’s leadership over the past few months.

Mr. Ackman touted the candidates’ military experience, and Mr. Zuckerberg’s candidate, Sam Lessin, is a venture capitalist and a former employee of Facebook (as Meta was formerly known).

But they could not surmount the first hurdle: collecting the 3,238 signatures from Harvard alumni to get their names on the ballot for the April election.